Device for controlling a computer system

ABSTRACT

The invention concerns a computer system ( 1 ), preferably of the personal microcomputer type, controlled by a group of users by means of several mouse-type pointing devices ( 3 ) without wired connection with the system ( 1 ). Each pointing device communicates by infrared with a console ( 38 ) connected to the system ( 1 ) through a communication port ( 50 ). A multifrequency transmission technique and a frequency hopping coding are used. The graphic interface of the system is projected ( 47, 48 ) on a large screen ( 49 ) for collective visual display. The console ( 38 ) comprises a detachable receiver horn ( 41 ) which enhances the range, and a set of switches ( 40 ) for selecting the mouse or mice controlling one or several cursors ( 54 ) of different shape and/or colour. The inventive device is particularly designed for collective initiation to microcomputing and collective training in using software.

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a device for controlling acomputer system, preferentially of the personal microcomputer type, bymeans of pointing devices, in particular of the wireless mouse type.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] The devices for controlling a computer system consisting inmoving by means of a mouse, trackball or another pointing device, acursor in order to indicate on the screen of the system an object, iconor element of a menu, representative of a function to be carried out,are well-known. If they were in the beginning reserved to professionalsworking on high range graphic consoles, they are today the symbol of thedemocratization of the use of the computer by removing the obligation tohave to learn esoteric process control languages. Even a child notknowing yet how to read cal play with a computer provided with a graphicinterface.

[0003] The manufacturers of pointing devices thus sought to make thoseof the most possible pleasant use. A constraint, generally aggravating,is the presence of the wire connecting the mouse to the centralprocessing unit, and being used at the same time for the transmission ofthe data in series mode and for the power supply. This wire is alwaystoo short or clings to the most various objects. A mouse without wire isthus regarded as an improvement.

[0004] Such a pointing device is described in the European patentapplication EP0171747, in the name of METAPHOR COMPUTER SYSTEMS Company,published on Feb. 19, 1986. The device transmits its displacements andthe states of its command buttons to the central processing unit bymeans of an infrared beam of light modulated in amplitude by thesequences of representative binary digits. The implementation of aninfrared base band transmission is extremely simple, but it can appearreception problems due to the ambient light, which can present spectralcomponents in the near infrared (Sun, incandescent lamps). It was thusrequired an improvement of the reception by using means of concentrationand guidance of the received light.

[0005] The Japanese patent application JP4205129, in the name of HITACHILTD Company, published on Jul. 27, 1992, features such a system.

[0006] Another technical problem is set by the power supply of thewireless mouse. Suppression of the wire constraint leads to anotherconstraint obligation to reload the battery periodically before thedevice ceases functioning. EP017747 application brought a partialresponse to this problem by transmitting to the central processing unita message of alarm intended for the user.

[0007] The European patent application EP0849700, by the PHILIPSPATENTVERWALTUNG and PHILIPS ELECTRONICS companies, published on Jun.24, 1998, proposes a feeding of the wireless mouse by an inductive loopplaced in the mouse pad. The wire of the mouse is actually removed, butthe problem is moved on the level of supplying electric power in theappropriate form to the pad. A new wire is thus necessary; moreover, theuser is limited in his aesthetic choices of this accessory, since thepad is obligatorily of a model especially adapted to the system.

[0008] The power supply is not a question being asked only for pointingdevices of computer. It is asked for all small electronic instruments.Generally, cells are used. The periodic replacement of those can becomeexpensive for the user, and one uses batteries more and more commonly,at the price of a more significant starting investment, in particular ina charger. For low powers, a mixed feeding by battery and solar cell,the battery playing a role of buffer, is known since the appearance onthe market of cheap amorphous silicon cells. It is the case of pocketcalculators or of office calculating machines. The devices described inthe Japanese patent applications JP56132653 and JP61210828, respectivelyin the name of SEIKO EPSON CORP and of CASIO COMPUTER CO LTD, areexamples among others.

[0009] The embodiment of a solar cell power supply in a wireless mouseimplementing an infrared connection is described in the British patentapplication GB2292995, in the name of PRIMAX ELECTRONICS LTD, publishedon Mar. 13, 1996.

[0010] The improvements of the basic pointing device largely known inthe field of microprocessing, relate only to the individual use of aninformation processing system. One knows possibilities of co-operatingwork of several people by the setting of several central processingunits connected by a network. However, even if work is collective, eachperson personally controls each central processing unit by means ofher/his own pointing device.

[0011] A system making it possible to several people to use the samecentral processing unit is described in the Japanese patent applicationsJP8221194 and JP9146703, in the name of NTT Company, publishedrespectively on Aug. 30, 1996 and on Jun. 6, 1997. The commands comingfrom several wireless mice can be received by a conventionalmicrocomputer. To this end, a time-sharing radio transmission techniqueis implemented. The various mice transmit successively their data whenthey receive an identifying code sent by the basic station connected tothe central processing unit corresponding to their own codes. Theenvisaged use is that of education and game.

[0012] The Japanese patent application JP10040002, in the name of NECCompany, published on Feb. 13, 1998, described simultaneous operation ofseveral mice in the same window.

[0013] The concept of a set of pointing devices controlling a singleinformation processing system presents interesting prospects inparticular in leaching. Contrary to the teaching of other disciplines,data-processing practices lends itself currently rather badly tocollective courses. The training is rather based on the setting ofpractical working sessions, during which the pupils, by small groups oftwo or three, are exerted on a complete microcomputer. To let a greatnumber of pupils to profit from an initiation, one thus needs averageconsiderable hardware permanently installed in specialized classrooms,having many power supply plugs.

[0014] The wireless mouse systems described above in the JP9146703,JP8221194 and JP10040002 patent documents would allow on the contrary amore traditional approach of initiation into handling of a computer.Each pupil having a mouse, could, under the control of a trainer, learnhow to use a graphic interface, the image of which could be projected ona large-sized screen by means of an adapted data-processing peripheral,such as a video projector, or a LCD tablet adapted to an overheadprojector.

[0015] The economic advantage is obvious: only one informationprocessing system is enough, which could consist of a portablemicrocomputer. The specialized rooms are not necessary any more, and theequipment can be installed quickly in any room. However, this economicadvantage is a bit limited by the complexity of the known systems. Thedata transmission protocols between the mice and the central processingunit rely on microwave links, which force each pointing device tocomprise a receiver to receive synchronization signals. Radio linkspresent also many disadvantages in countries where there areconstraining regulations with regard to frequency bands allowed for datatransmission. The number of these bands is restricted and the remainingbands are extremely encumbered, therefore the use of complex data codingmethods is mandatory to avoid a disturbance by a similar systemoperating in the vicinity.

[0016] The recourse to an infrared link would thus seem more suitable,the channels of communication by this means inside a room beingpreserved from external disturbances. Moreover, the system couldimplement electronic components having very great diffusion, sinceinfrared remote control systems are of universal use.

[0017] The system requires at least a number of communication channelsat equal to the number of pointing devices, and must be insensitive tothe ambient light, but modulation techniques having the desiredcharacteristics exist. One can quote the frequency shift keying of asubcarrier, an example of which is given in the European patentapplication EP0342146, in the name of TRANSDATA Company, published onMay 11, 1989. The described device relates to only one bi-directionalconnection between an electric meter and an apparatus intended to pickup power consumption, and the implemented method could not thus bedirectly applied. However, hie demodulation method described in thisdocument, based upon cabled electronics, can be replaced easily byequivalent software processing.

[0018] The European application EP0924873, in the name of ALCATELCompany, published on Jun. 23, 1999, is describing an algorithm allowingthe detection of the answering tone of modems and telecopiers.

[0019] This type of algorithm of the Goertzel type, is well known, andcan apply to the detection of voice frequencies. The necessarysignificant computing power implies the use of dedicated digital signalprocessing circuits, like those manufactured by ADVANCED MICRO DEVICESCompany. This company reveals besides an improvement of the Goertzelalgorithm in the international patent application WO97/20438, publishedon Jun. 5, 1997. In the technical note “DTMF Tone Generation andDetection: An implementation Using the TMS320C54x” (Application Report;SPRA096A- May 2000), the TEXAS INSTRUMENTS Company describe algorithmsto make synthesis and detection of signals in a multifrequency system.

[0020] It appears from the state of the art as described in thedocuments quoted above, that sets of pointing devices intended for auser group for controlling a common information processing system areknown, but that there is not to date any simple, robust and cheap systemrelying on trusted and modern techniques, which can really beimplemented in particular with a view to teaching by carrying out aninventive synthesis of the state of the art in order to obtain optimalcharacteristics.

SUMMARY OF THE INVENTION

[0021] The present invention thus aims at optimizing the design of adevice for controlling an information processing system.

[0022] It precisely has as an aim a device for controlling aninformation processing system, preferentially of the personalmicrocomputer type, provided with, in a known way, a graphic interface,and at least a communication port, by a user group by means of severalpointing devices without wired connection with the system,preferentially of the wireless mouse type. Each pointing device ishandled by each user and transmits by means of a communication channelsequences of binary data representative of displacements and states ofthese pointing devices to an electronic interface box connected to thecommunication port.

[0023] The device for controlling a computer system object of thisinvention is remarkable in that the communication channel comprises aplurality of secondary communication channels, transmitting with astandard modulation rate the binary data sequences, formed by a commoninfra-red carrier and a set of subcarriers modulated in amplitude by thebinary digits of these sequences. The frequencies of the subcarriers aredifferent for each pointing device, without common harmonic, and aredistributed between a lower frequency and a higher frequency, withintervals at least equal to the double of the value of the modulationrate increased by a guard band.

[0024] In an advantageous way, the frequencies of the subcarriers areequal to prime numbers multiplied by a constant coefficient.

[0025] In a first mode of realization of the invention, only onesubcarrier is assigned to each pointing device.

[0026] In a second mode of realization, one assigns to each pointingdevice two subcarriers modulated in opposition of phase by the binarydigits of the sequences.

[0027] In the first mode of realization of the invention, the controlsystem features pointing devices that comprise each one:

[0028] a) a block of digital processing of the signals includingpreferentially a microcontroller working out the binary digits

[0029] b) a block of emission including:

[0030] an oscillator, preferentially with interchangeable ceramicresonator, tuned on harmonic N of the frequency of the subcarrierassigned to the pointing device

[0031] a frequency divider by N producing the subcarrier starting fromits harmonic

[0032] a modulator of the subcarrier by the binary digits producing themodulated signals

[0033] a band pass filter with a center frequency equal to that of thesubcarrier and a bandwidth equal to the interval of frequency decreasedof the guitar band, generating filtered signals starting from themodulated signals.

[0034] an amplifier feeding one or more diodes emitting an infrared beamof light starting from the filtered signals.

[0035] c) a power supply unit including:

[0036] a solar cell

[0037] a battery

[0038] a regulator of the load of the battery by the solar cell

[0039] a DC/DC converter

[0040] In the second mode of realization of the invention, the controlsystem features pointing devices that comprise each one:

[0041] a) a block of digital processing of the signals preferentiallyincluding a microcontroller provided with:

[0042] a first program working out the binary digits

[0043] a second program constituting a digital oscillator working outthe samples of the modulated subcarriers.

[0044] b) a block of emission including:

[0045] a digital analog converter for converting the sampled subcarriers

[0046] a band pass filter with a center frequency equal to that of thesubcarrier and a bandwidth equal to the interval of frequency decreasedof the guard band, generating filtered signals starting from themodulated signals.

[0047] an amplifier feeding one or more diodes emitting an infrared beamof light starting from the filtered signals.

[0048] c) a power supply unit including:

[0049] a solar cell

[0050] a battery

[0051] a regulator of the load of the battery by the solar cell

[0052] a DC/DC converter.

[0053] An additional feature of the first mode of realization is thatthe electronic box comprises:

[0054] a) a block of reception of the infrared light signals and ofdetection of the subcarriers.

[0055] b) a block of frequential demutltiplexing of the detected signalsincluding a number of analog band pass filters equal to the number ofpointing devices.

[0056] c) a block of digital processing of the signals preferentiallyincluding a microprocessor provided with a communication program workingout the binary digits starting from the demultiplexed signals andtransmitting them to the communication port by means of a lineamplifier.

[0057] An additional feature of the second mode of realization, whichalso constitutes an alternative of the first mode, is that theelectronic box comprises:

[0058] a) a block of reception of the infrared light signals and ofdetection of the subcarriers.

[0059] b) a block of digital processing of the signals including:

[0060] an analog/digital converter of the detected signals

[0061] a microprocessor, or similar, provided with a Discrete FourierTransform algorithm for extracting the spectral information of thedetected signals, preferentially a two poles digital filter withinfinite impulse response of the Goertzel type, and a communicationprogram working out the binary digits starting from this information andtransmitting them to the communication port by means of a lineamplifier.

[0062] In one or the other of the modes of realization described above,the line amplifier is bi-directional and transmits to themicroprocessor, or similar, sequences of binary data representative ofdisplacements of an additional pointing device.

[0063] Very advantageously, the electronic box of the device forcontrolling a computer system according to the invention comprises adistinct part including the block of reception, provided with acollecting horn of the beams of infra-red light, and linked by ashielded cable to the principal part connected to the communicationport.

[0064] Contributing to the goals of the invention, the electronic boxcomprises a principal part in form of console provided with switchesmaking it possible to select one or more pointing devices and to makeinoperative the others.

[0065] Advantageously, the binary digits emitted by each pointing devicetransmit moreover periodically sequences of binary data for signalingthese devices so that an alarm is set off when any of these sequences isnot received any more by the electronic box after a predetermined amountof time.

[0066] According to the invention the binary digits transmit moreoversequences of binary data characteristic of the integrity of eachpointing device, preferentially of the presence of the ball in thewireless mouse type.

[0067] It is also advantageous that each pointing device comprisesmoreover push buttons in a number at least equal to 2, preferentially 7,whose sequences of binary data representative of their states areincluded in the aforementioned binary digits.

[0068] One will draw a great benefit from tie use of the control deviceaccording to the invention in particular for an information processingsystem including:

[0069] a central processing unit preferentially of the portable computertype.

[0070] a peripheral display preferentially of the LCD tablet typeadaptable to an overhead projector, or a portable video-projector

[0071] an application software set of the office automation orcommunication type, or specific of a function or a trade and when thisuse is collective initiation with microprocessing and collectivetraining to the use of that software.

[0072] One will also draw benefit from the use of the control deviceaccording to the invention with the same hardware supporting anapplication software bundle of the computer-assisted presentation type,preferentially in the case of commercial presentation making it possibleto an individual of a group of customers to choose a product or serviceby means of the pointing devices, and to visualize information aboutthis product or service.

[0073] Another advantageous use of the device for controlling a computersystem according to the invention with the above configurationimplements an application software set of the computer-assisted learningtype. This use is preferentially the collective taking ofmultiple-choice examinations the answers of which are selected by meansof the push buttons of the pointing devices.

[0074] Preferably, the computer system, the pointing devices, and theelectronic box are placed on a trolley held at the disposal of theusers, that they are coaches, presenters or teachers, to be taken alongand used in buildings not presenting special electric wiring.

[0075] The advantages of these various uses are still increased when theinformation processing system comprises moreover keyboard simulationsoftware making it possible to simulate a keystroke by pointing thesimulated image of this key by means of one of the pointing devices.

[0076] The users appreciate the use of the device according to theinvention when the information processing system comprises moreover asoftware allotting a cursor of different form and/or color to eachpointing device according to the identifying binary data sequences ofthe transmitting pointing devices included in the signals by thecommunication program of the electronic box.

[0077] These few essential specifications, resulting from the optimaldesign of the device for controlling a computer system, make obvious forthe expert the advantages brought by the invention compared to thebackground art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0078]FIG. 1 is a diagram of the device for controlling a computersystem by a group of users according to the known general concept of thestate of the art.

[0079]FIG. 2 is an explanatory diagram of the frequency multiplexingmethod implemented in the device for controlling a computer systemaccording to the invention.

[0080]FIG. 3 is a simplified electronic diagram of each pointing deviceof the control device according to a first mode of realization of theinvention.

[0081]FIG. 4 is a simplified electronic diagram of the electronic box ofthe control device according to a first mode of realization of theinvention.

[0082]FIG. 5 is a simplified electronic diagram of each pointing deviceof the control device according to a second mode of realization of theinvention.

[0083]FIG. 6 is a simplified electronic diagram of the electronic box ofthe control device according to a second mode of realization of theinvention.

[0084]FIG. 7 is a diagrammatic general view of the electronic box of thedevice for controlling a computer system according to the invention.

[0085]FIG. 8 is a diagrammatic view of the collecting horn, which theelectronic box comprises.

[0086]FIG. 9 is a general view of an information processing system usingthe control device according to the invention.

[0087]FIG. 10 is a general view presenting a preferential use of theinformation processing system of FIG. 9.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0088] The references on FIGS. 1 to 10 will be used to explain indetails the various characteristics of the invention.

[0089] The general concept of the device is illustrated by FIG. 1. Amicrocomputer 1 comprises an operating system presenting a graphicinterface that allows users to interact with the system by means of ascreen display 2 and pointing devices 3. The signals emitted by thepointing devices 3 are received by an electronic box 4 connected to acommunication port 5, generally a serial port, of the central processingunit 1.

[0090] In a common microcomputer system under WINDOWS®, the pointingdevices are mice, or track-balls which communicate their displacementsand the actions of the user on their control buttons (clicks) to theoperating system by a RS232 link. For MICROSOFT® compatible mice, X andY displacements, and the right R and left L buttons states are coded inthree words comprising 1 START bit, 7 data bits, and 2 STOP bits,transmitted at 1200 bauds. To be compatible with any system underWINDOWS® by emulating a compatible mouse, the electronic box 4 has thusan operating mode in which he binary sequences of data emanating of allthe mice are transmitted with this format and at this speed by theserial communication port 5.

[0091] In a first mode of realization of the device according to theinvention, all the elements of a standard mouse are included in order tocarry out economies of scale. For each one of these mice, it is thus aquestion of transmitting by infrared a set of binary sequences of datahaving a modulation rate of 1200 bauds. The total number of mice wasselected equal to 32, both for practical reasons (It is the size of aclass) and technical reasons (Number of bits of the ports and buses ofmicroprocessors used).

[0092] In a second mode of realization, not relying any more on standardelements, the majority of the electronic functions being carried out bydigital processing of the signals, a modulation rate of 1200 bauds willbe however preserved for compatibility reasons.

[0093] The selected infra-red data transmission technique is a frequencymultiplexing technique limited in a lower and upper range of a frequencyband, either by the characteristics of the band pass filters used in thefirst mode of realization, or by the number of nominal MIPS of themicroprocessors implemented in the second mode of realization.

[0094] In the realization with analog electronics, only one subcarriermodulated in amplitude is assigned to each mouse in order to limit thecomplexity of the electronic box 4.

[0095] The numerical realization allows the use of a greater number offilters for the demultiplexing without increase in complexity. Twosubcarriers are assigned to each mouse. The two subcarriers aremodulated in opposition of phase by the binary digits of the frames ofbits emanating from the sensors of the mouse, so it means, in fact thata frequency shift keying (FSK) modulation increasing considerably theS/N ratio of the transmission is used.

[0096]FIG. 2 shows the distribution of the frequencies of thesubcarriers P1, P2 between a lower frequency F1 and an upper frequencyF2.

[0097] To satisfy Nyquist criterion, the frequency band allocated toeach pointing device is at least 2400 Hz; the interval C1, C2 betweeneach subcarrier P1, P2 is thus at least 2400 Hz.

[0098] The band pass filters used in the first mode of realization aretone decoders, for example of the LM567 type from NATIONAL SEMICONDUCTORCompany. For this circuit, the maximum bandwidth ΔF is related to thecenter frequency F0 by the relation: ΔF=F0/0,14.

[0099] The lower frequency F1 must thus be higher than 17 KHz.

[0100] To prevent that subcarriers have common harmonics, theirfrequencies are equal to prime numbers multiplied by a constantcoefficient. The following table gives examples of the frequencies usedfor the 32 secondary transmission channels in this mode of realization.Subcarrier Clock frequency Channel Prime number frequency (Hz) clock(Hz)  1 113 22600 180800  2 139 27800 222400  3 157 31400 251200  4 17334600 276800 . . . . . . . . . . . . 30 617 123400  987200 31 631126200  1009600  32 647 129400  1035200 

[0101] The constant coefficient is equal to 200.

[0102] The interval C1, C2 between the frequencies of the subcarriersP1, P2 is approximately of 3 KHz, which spares an acceptable guard bandB. The lower limit F1 of the communication channel is F1=19600 Hz, theupper limit is F2=130900 Hz.

[0103] In the second realization mode, relying on numerical oscillators,there are no more constraints on F1 and F2, and the guard band could besmaller. For compatibility reasons, the same distribution of frequencieswas kept. There are thus 64 frequencies with an interval of 3 KHz from22600 Hz.

[0104] The table above shows a clock frequency.

[0105] As FIG. 3 shows it, each subcarrier P1, P2 is indeed produced byanalog means starting from its eighth harmonic.

[0106] An oscillator 6 stabilized by a ceramic resonator 7 generates asquare signal the frequency of which is divided by eight by a binarycounter 8. The ceramic resonators used are resonators of the CERALOCK®type having suitable precision and frequency band.

[0107] The square signal at the frequency of the subcarrier P1, P2 isswitched 9 by the binary signals coming from a microcontroller 10processing the signals from the incremental position sensor 11 of thepointing device 3, and the buttons 12.

[0108] The microcontroller 10 and the sensors 11, 12 form a block ofdigital processing of the signals 13, which is preferentially a standardmouse electronic module. For example, a microcontroller of the COP800type from NATIONAL SEMICONDUCTOR Company was used.

[0109] The modulated square signals are filtered by a band pass filter14 the center frequency of which is that of the subcarrier P1, P2 andthe bandwidth of which is equal to 2400 Hz. The resulting signal isapplied to an amplifier 15, which attacks an infrared emitting diode 16.The diode used is a diode the reference of which is SFH415-T, fromSIEMENS Company, whose emitting power at 950 nm lies between 25 and 50mW per steradian.

[0110] The unit including the oscillator 6, the divider 8, (le filter14, the amplifier 15 and the infrared diode 16 constitutes a block ofemission 17 which is preferentially inserted in a basic element of astandard mouse 13.

[0111] The power supply unit 18 is another significant element of thepointing device. It includes a solar cell 19 charging a battery 20through a regulator 21. The various tensions necessary to the circuitsare generated by a DC/DC converter 22 starting from the tension of thebattery 20.

[0112]FIG. 4 schematically shows the receiver of the signals transmittedby the pointing devices according to the first mode of realization ofthe invention.

[0113] The block of reception 23 includes a photodiode 24 receiving thebeams emitted by the pointing devices 3 AC coupled to the input of acurrent amplifier 25. This amplifier 25 is followed by a second stage26, and by two filters 27, 28 for rejecting the 50 Hz and 100 Hzcomponents which can be present in the signal (or 60 Hz and 120 Hzcomponents, according to the localization).

[0114] The spectral characteristics of the photodiode 24 are adapted tothose of the emitted light. A photodiode 24 of the BPW34-F type, fromSIEMENS Company, presenting a maximum of sensitivity at 950 nm andprovided with an ambient light filter, is used. The amplifiers 25, 26are circuits of the LM 13700 type from NATIONAL SEMICONDUCTOR Company,which comprise two transconductance amplifiers which can be wired asamplifiers with automatic gain control (AGC).

[0115] The amplified signals are transmitted to a demultiplexing block29 made of a set of tone decoders 30, each one generating a logicalsignal 0 when a signal has a frequency within its respective bandwidth.

[0116] The logical signals are processed in a digital processing block31 by a microprocessor 32 a parallel port of which acquires theselogical signals which are memorized by a set of 3-state latches 33. Theprogram of tie microprocessor 32 takes into account the data of theregisters 34, representative of a selection of pointing devices and ofan operating mode, to generate the binary digits transmitted by means ofa line amplifier 35 to the communication port 5 of the centralprocessing unit 1. The line amplifier 35 being bi-directional, themicroprocessor also receives frames of data transmitted by the centralprocessing unlit 1, in particular from its own internal pointing device(a trackball or similar), or from an additional mouse connected to anauxiliary port of case 4.

[0117] The components that are used are logical circuits of everydayusage. As a nonrestrictive example, the following circuits wereimplemented:

[0118] microprocessor 32: MC68705P3 from MOTOROLA Company

[0119] 3-state latches 33: DM74LS534 from FAIRCHILD Company

[0120] registers 34: DM74LS374 from FAIRCHILD Company

[0121] line amplifier 35: MAX232 from MAXIM Company.

[0122] In this example of embodiment, the microprocessor which is useddoes not comprise a serial communication port, therefore an interfacecircuit of the asynchronous communication interface adapter (ACIA) typeis implemented (MC6850 circuit reference of MOTOROLA Company)

[0123] In a second mode of realization of the internal electronics ofeach pointing device 3, the generation of subcarriers P1, P2 isimplemented by an entirely numerical method. As FIG. 5 shows it, theblock of emission 3 is thus simplified. The microcontroller 10comprises, in addition to the program, which is used to generate thebinary digits representative of the displacements and of the state ofthe mouse, a second program working as a numerical oscillator. Thenecessary computing power is significant, and is estimated at a few tensof MIPS, but the available power supply is limited. A circuit of theTMS320C54x type from TEXAS INSTRUMENTS Company was thus selected for itslow power (Supply voltage 3.3 V; 0,54 mW/MIPS). The algorithm isdescribed in the various application notes that are published by thiscompany and will not be added here. The samples of the modulatedsubcarriers are transmitted to a digital analog converter 36, thenapplied to the same components as in the block of emission 3 of thefirst mode of realization: band pass filter 14, amplifier 15, andinfrared diode 16.

[0124] In this mode of realization, 64 subcarriers are used. The higherfrequency exceeds 200 KHz. The Shannon sampling theorem thus prescribesa sampling rate of more than 400 Khz. Taking into account the problemarising from the electric power balance, the converter 36 of the AD7524type from ANALOG DEVICES Company was selected.

[0125]FIG. 6 also shows that the electronic box is simplifiedconsiderably in this mode of realization, since die set of tone decoders30 disappeared. The decoders 30 are replaced by only one analog/digitalconverter 37 which places the samples of the detected signals on thedata bus of the microprocessor 32.

[0126] For the same reasons as previously, this converter 37 is a fastconverter. The model that is appropriate is a circuit of the AD7822 typefrom ANALOG DEVICE Company, able to reach a maximum sampling rate of 2MSPS.

[0127] The Goertzel algorithm which is used to extract spectralinformation from the sampled signal is a particular case of calculationof a discrete Fourier transform, and will not be explained in detailshere, insofar as all the explanations appear in the technical note “DTMFTone Generation and Detection: an implementation Using the TMS320C54x”(Application Report; SPRA096A-May 2000), published by TEXAS INSTRUMENTSCompany, already quoted.

[0128] According to indications given in this document, the processingof the 64 sampled channels which are sampled at 500 KHz rate needs acomputing power close to 200 MIPS.

[0129] This second mode of realization does not call for otherparticular observations, insofar as the main part of five functions ofthe electronic box are carried out by software modules of existinglibraries, which were adapted.

[0130] The case inside which the above mentioned electronic elements areplaced, is shaped, as FIG. 7 shows it, like a console 38. The higherpart 39 presents a set of 32 switches 40 making it possible to selectone or more pointing devices 3 and to make inoperative the others. Thestates of these switches 40 are memorized in registers 34 read by themicroprocessor 32. The console 38 also comprises a selector of theoperating mode of the electronic box 4. Three basic operating nodes arepossible:

[0131] a first operating mode where only one mouse 3, selected by one ofthe switches 40, acts on the central processing unit 1.

[0132] a second operating mode where all the mice act on the same cursor54

[0133] a third operating mode where each mouse acts on a cursor 54 whichis its own one

[0134] The selected basic operating mode is also memorized in a register34, and is read again by the microprocessor 32 that launches theadequate program. In an alternative of the second and third modes, themice 3 that act on the cursors are selected by the switches 40.

[0135] The electronic box 4 comprises a part, distinct 41 from theconsole 38, including the whole reception block 23. This part 41 isconnected by a shielded cable 42 to the console 38, and is generallydistant from it in operation, but is locked with it if circumstances arefavorable. It comprises indeed an antenna horn 43 intended to collectthe beams of infrared light emitted by the mice 3. The collecting horn43 is placed in height, and is laid out in order to cover the entirezone where mice 3 are used. The cable 42 ensures the power supply of theblock of reception 23 and the transmission of the detected signalstowards the console 38. As FIG. 8 shows it, the antenna horn 43 has thegeneral shape of a truncated pyramid with a square base, forming afunnel. A red filter 44 is placed at the entry. The internal walls 45are silver plated and reflect the collected infrared rays towards thephotodiode 24. An antenna the base of which measures 30 mm×30 mm, thesection at the level of the photodiode 9 mm×9 mm, and the height is 60mm gave good results. Incidentally, this part 41 which contains the horn43 and the block of reception 23, and matches the shape of the console38 by prolonging it when it is locked with it, includes a housing 46 toplace folded up cable 42.

[0136] In the first mode of realization of each pointing device 3, anelectronic module of a standard mouse is used preferably. Thiselectronic unit generally includes a specialized integrated circuit (Forexample the TP8375 serial mouse controller TP8375 from Topro TechnologyInc Company) by means of which the functionalities of a standard mousecomprising a ball and three push-buttons are implemented.

[0137] As it will be further described, particular applications will usewith profit push buttons in a number higher than 2 or 3 traditionalbuttons. In this case the binary digits switching the subcarrier P1, P2must contain the sequences of binary data representative of theseadditional buttons. These sequences are generated either by a specificcabled logic, or by a microcontroller, and are inserted in the flowcontrolling the transmitting diode 16 by an OR gate in the timeintervals when the standard electronic unit does not transmit data.

[0138] In the same way binary sequences of the pointing device 3signaling data can be transmitted periodically. Received normally by theinterface electronic box 4 at regular time intervals, the loss of thereception of these signaling sequences means anomaly of the pointingdevice 3, disturbance of the infrared link, or voluntary dissimulationof the pointing device 3 involving the screening of the transmittingdiode 16.

[0139] An infrared connection has thus an advantage compared to aconnection by Hertzian waves, because a pointing device 3 cannot becarried apart from the room where the interface electronic box 4 iswithout that being immediately detected. If the console 38 were providedwith indicators beside each switch 40, the flickering of thecorresponding indicator makes it possible to announce the pointingdevice about to be stolen. This anti-theft function is a significantcharacteristic for a device of which the use is mainly collective.

[0140] In the same way, with a similar aim, sequences of binary datacharacteristic of the integrity of each pointing device 3 can also betransmitted. The unauthorized disassembling of the various elements ofthe pointing device 3 (case, battery 20, ball . . . ) is easily detectedby micro-switches, or any other type of sensors.

[0141] A modification of the state of these sensors is transmitted tothe electronic box 4 and sets off either all alarm on case 4 itself, oran alarm on the information processing system 1. This anti-disassemblingfunction is also significant for a public use.

[0142] Other types of alarms can be started by each pointing device 3. Aspecial button switched by the user of a pointing device can start theflickering of the corresponding indicator on the console 38, in order todraw attention. To facilitate the maintenance of each pointing device 3,messages concerning their operation can be transmitted, in particularthe load state of the battery 20.

[0143] All these functionalities (theft protection device,anti-disassembling, call, and assistance with maintenance) are moreeasily implemented in the second mode of realization by software.However, all the combinations are possible between the first and secondmodes of realization described in details above.

[0144] For example, nonrestrictive, if the standard mouse element is notbased on a specific integrated circuit, but on a microprogrammedmicrocontroller, the microcode will be modified consequently.

[0145] The man skilled in the art will be able to consider many otherways of fulfilling the basic functions of each pointing device 3 and ofthe electronic interface 4.

[0146] So the oscillator 6 for generating the subcarrier P1, P2 of eachpointing device will not be inevitably stabilized by a ceramic resonator7, or with quartz. The circuit could be a pulse generating circuit withan external RC network, having a good temperature stability and withrespect to the variations of the supply voltage, such as for example anintegrated circuit of the timer type. The higher harmonics of theproduced square signals will not be necessarily filtered with theemission, those in fact being largely attenuated by the limitedband-width of the receiving photodiode 24 and of the block of reception23. It could be also a voltage-controlled oscillator (VCO), inparticular if two subcarriers P1, P2 are used. These simplificationstake place if the number of necessary pointing devices 23 is lower than32, for example 16, 8 or 4, for particular applications.

[0147] In the first mode of realization, the baud pass filters used arepreferentially very selective tone decoders, but with relatively narrowsensitivity range. High Q active filters, based on operationalamplifiers, can alternatively be implemented. In case of unfavorablesignal/noise ration, phase locking loops could be selected.

[0148] The mode of connection described at present between theelectronic interface box 4 and the information processing system 1 is aserial connection of the RS22 type. This mode of connection is mostwidespread. However, the expert will not have any difficulty inreplacing RS232 interface by an interface of the PS/2 or even the USB(Universal serial bus) type.

[0149] As it was already indicated, tile goal of this control device ofan information processing system is to offer a new means of collectivetraining to the microprocessing techniques.

[0150] A suitable computer system using the control device according tothe invention is represented on FIGS. 9 and 10, without this examplebeing restrictive.

[0151] This system includes:

[0152] a portable computer 1 under WINDOWS®

[0153] a LCD tablet 47 connected to tile video outlet of the computer 1

[0154] an overhead projector 48 of the type usually used for theprojection of transparencies

[0155] a screen 49 on which is projected the image of the screen ofmicrocomputer 1.

[0156] The communication port 50 of the electronic box 4 is connected tothe mouse ports (Generally COM1) of the microcomputer. An additionalmouse 51 is connected to the auxiliary port 52 of case 4, if thetrackball 53 of the microcomputer 1 is not usable. The part 41containing the reception horn 43 is placed in order to collect thesignals emitted by the mice 3 as well as possible.

[0157] A LCD 47 tablet presenting a 800×600 points resolution (SVGA)usable with a projector 48 of strong luminosity is preferable.

[0158] Under the control of the trainer, the people handling mice 3learn how to move a cursor 54, and to use the various applicationsoftware modules installed on system 1.

[0159] In a graphic environment, the use of the keyboard is limitedenough; however the trainer has the possibility of displaying in bottomof screen 49 the image of a keyboard. The designation of the image of akey by a cursor simulates corresponding striking. This result isobtained by means of application software suitable for the operatingsystem.

[0160] The normal use of the control device according to the invention,seems to be the first operating mode in which each person hassuccessively the possibility of acting on only one cursor 54, becausethat corresponds to die usual rule of speech in group.

[0161] However teaching projects could make profitable the thirdoperating mode of the device, where each person has her/his own cursor54, provided that the application software lend themselves or areadapted to it.

[0162] With this goal, in this last operating mode, the communicationprogram of microprocessor 32 incorporates in the binary digitstransmitted to the central processing unit 1 binary sequences of data ofidentification of the pointing devices transmitting these signals. Thesesequences are treated, insofar as there is no incompatibility with thetype of operating system under which the central processing unitfunctions 1, by a driver suitable for interface 4 to visualize thecursors assigned to each pointing device 3. All cursors 54, of differentform and/or color for each running pointing device 3, can appearsimultaneously on the screen 49, or only the cursors 54 corresponding todevices 3 selected by console 38.

[0163] Software using the specific functionalities of the control deviceof an information processing system object of this invention could bedeveloped by the educational software publishers. For example, softwareallowing the collective taking of multiple-choice examinations (MCE).For a questionnaire with three possible answers, a pointing device 3only provided with the three traditional buttons is enough. Thequestions are displayed automatically during a given time on screen 49to the sight of the pupils. Each one of those selects her/his responseby means of the mouse buttons. The results of the MCE and the statisticsof the class are automatically calculated at the end of the test. Morecomplex MCE will make profitable the additional buttons of pointingdevices 3.

[0164] In order to increase the simplicity of implementation of thecontrol device of a computer system 1 according to the invention, and todraw the maximum of benefit of its use, thus one could be added to theelements of the multi-media trolley, already ii use in schoolestablishments. This trolley, a kind of special piece of furniture oncasters, supports a central processing unit 1 of the PC type, withkeyboard, mouse, CD-Rom or DVD player, loudspeakers, screen, andprinter. It can be moved from classroom to classroom, without specialwiring, according to needs, to carry out demonstrations of software. Itis conceived easily that the control device of an information processingsystem according to the invention will bring an outstanding dimension tothe multi-media trolley.

[0165] Other collective uses of the device are possible, in particularin the field of the commercial presentation. These presentations arecurrently carried out using software of the computer-assistedpresentation (CAP) type. They are not interactive, and the customer orprospective customer must undergo the statements of the representativepassively. By means of the device according to the invention, thecustomers can direct the presentation according to their wishes whileclicking on the links returning to the aspects of the product or theservice which interest them. On this principle, promotional operationscould be organized in the supermarkets.

[0166] A video-projector connected to the computer system comprising themultiple wireless mice according to the invention can also create avirtual shop-window: each customer selects the desired product by meansof the cursor corresponding to the pointing device with which she/he wasprovided, and can zoom the image of the product, or obtain otherinformation, like price or availability. A product not appearing in theshop-window can be called starting from menus or lists. Several productscan be visualized simultaneously by the customers. Each customer canpossibly place the order of the article that she/lie selected, andrecover later on this article at the desk starting from a commandreference.

[0167] The potential uses of the control device of an informationprocessing system according to the invention are thus multiple, andcompletely renew the collective applications of microprocessing in aprospect different from existing network and workgroup applications.

[0168] They are not dependent on any particular data-processingenvironment, in particular WINDOWS® for example, but are open on anyoperating system presenting a graphic interface, such as for exampleLINUX provided with X-WINDOW.

[0169] It is to be understood that the invention is not limited to theonly modes of carrying out the invention, given by way of examplesabove; it embraces, on the contrary, all the possible alternatives ofrealization. In particular all those resulting from all optimization ofthe device for a particular use, for example relating to:

[0170] the number of pointing devices, adapted to the maximum number offoreseeable participants, which inevitably affects the complexity of thedevice and thus its manufacturing cost.

[0171] the range adapted to small rooms, premises of average size orlarge rooms, lecture rooms, lobbies or others, which implies differentpowers of emission, possibly the implementation of several infra-reddiodes in parallel, or series-wound, in each pointing device.

[0172] conditions of ambient light: in particular fluorescent tubes, orsuit, in case of a use in full day, outside or under canopy.

[0173] the use in places where a dense crowd, smoke, water vapor,luminous flashes can disturb the infrared links (bars, dance-halls,theaters . . . )

[0174] would not depart from the new and inventive framework of thisinvention.

1) Device for controlling a computer system (1), preferentially of thepersonal microcomputer type, provided with a graphic interface (2) andat least a communication port (5), by a user group by means of severalpointing devices (3) without wired connection with said system,preferentially of the wireless mouse type, each one of said pointingdevices (3) being handled by each one of said users and transmitting bymeans of a communication channel sequences of binary data representativeof displacements and states of pointing devices (3) to an interfaceelectronic box (4) connected to said port (5), characterized in thatsaid channel comprises a plurality of secondary communication channels(C1, C2), transmitting with a standard modulation rate (R) saidsequences, formed by a common infrared carrier and a set of subcarriers(P1, P2) modulated in amplitude by the binary digits of said sequences,with different frequencies for each one of said pointing devices (3),without common harmonic, and distributed between a lower frequency (F1)and a higher frequency (F2), with intervals at least equal to the doubleof the value of the said modulation rate (R) increased by a guard band(B). 2) Device for controlling a computer system (1) according to claim1, characterized in that the frequencies of said subcarriers (P1, P2)are equal to prime numbers multiplied by a constant coefficient. 3)Device for controlling a computer system (1) according to any one ofclaims 1 or 2, characterized in that only one subcarrier (P1) isassigned to each one of said pointing devices (3). 4) Device forcontrolling a computer system (1) according to any one of claims 1 or 2,characterized in that two subcarriers modulated (P1, P2) in oppositionof phase by said binary digits are assigned to each one of said pointingdevices (3). 5) Device for controlling a computer system (1) accordingto claim 3, characterized in that each one of said pointing devices (3)comprises: a) a block of digital processing (13) of the signalsincluding preferentially a microcontroller (10) working out said binarydigits, b) a block of emission (17) including: an oscillator (6),preferentially with interchangeable ceramic resonator (7), tuned onharmonic N of the frequency of the subcarrier (P1) assigned to saidpointing device (3), a frequency divider (8) by N producing thesubcarrier (P1) starting from its harmonic, a modulator (9) of thesubcarrier (P1) by said binary digits producing of the modulatedsignals, a band pass filter (14) with a center frequency equal to thatof said subcarrier (PI) and a bandwidth equal to said interval decreasedof said guard band, generating filtered signals starting from saidmodulated signals, an amplifier (15) feeding one or more diodes (16)emitting an infrared beam of light starting from said filtered signals,c) a power supply unit (18) including: a solar cell (19), a battery(20), a regulator (21) of the load of the battery (20) by the solar cell(19), a DC/DC converter (22). 6) Device for controlling a computersystem (1) according to claim 4, characterized in that each one of saidpointing devices (3) comprises: a) a block of digital processing (13) ofthe signals preferentially including a microcontroller (10) providedwith: a first program working out said binary digits, a second programconstituting a digital oscillator working out the samples of saidmodulated subcarriers b) a block of emission (17) including: adigital/analog converter (36) for converting said samples, a band passfilter (14) with a center frequency equal to that of said subcarrier(P1, P2) and of bandwidth equal to the said interval decreased of saidguard band, generating filtered signals from said modulated signals, anamplifier (15) feeding one or more diodes (16) emitting an infrared beamof light starting from said filtered signals, c) a power supply unit(18) including: a solar cell (19), a battery (20), a regulator (21) ofthe load of the battery (20) by the solar cell (19), a converter DC/DC(22). 7) Device for controlling a computer system (1) according to claim5, characterized in that said electronic box (4) comprises: a) a blockof reception (23) of the infrared light signals and of detection of saidsubcarriers, b) a block of frequential demultiplexing (29) of thedetected signals including a number of analog band pass fillers (30)equal to the number of said pointing devices (3), c) a block of digitalprocessing (31) of the signals preferentially including a microprocessor(32) provided with a communication program working out said binarydigits starting from the demultiplexed signals and transmitting them tothe communication port (5) by means of a line amplifier (35). 8) Devicefor controlling a computer system (1) according to any one of claims 5or 6, characterized in that said electronic box (4) comprises: a) ablock of reception (23) of the infrared light signals and of detectionof said subcarriers (P1, P2), b) a block of digital processing (31) ofthe signals including: an analog/digital converter (37) of the detectedsignals, a microprocessor (32) or similar provided with a DiscreteFourier Transform algorithm for extracting the spectral information ofsaid detected signals, preferentially a two poles digital filter withinfinite impulse response of Goertzel type, and a communication programworking out said binary digits starting from said information andtransmitting them to said port (5) by means of a line amplifier (35). 9)Device for controlling a computer system (1) according to any one ofclaims 7 or 8, characterized in that said line amplifier (35) isbidirectional and transmits to said microprocessor (32) or similarsequences of binary data representative of displacements of anadditional pointing device (51). 10) Device for controlling a computersystem (I) according to any one of the preceding claims, characterizedin that said case (4) comprises a distinct part (41) including saidblock of reception (17), provided with a collecting horn (43) of saidbeams, and linked by a shielded cable (42) to the principal part (38)collected to said port (5). 11) Device for controlling a computer system(1) according to any one of the preceding claims, characterized in thatsaid electronic box (4) comprises a principal part (38) in form ofconsole provided with switches (40) making it possible to select one ormore of said pointing devices (3) and to make inoperative the others.12) Device for controlling a computer system (1) according to any one ofthe preceding claims, characterized in that said binary digits transmitmoreover periodically sequences of binary data for signaling saidpointing devices and in that an alarm is set off when any of saidsequences of binary data for signaling is not received any more by saidelectronic box (4) after a predetermined amount of time. 13) Device forcontrolling a computer system (1) according to any one of the precedingclaims, characterized in that said binary digits transmit moreoversequences of binary data characteristic of the integrity of each one ofsaid pointing devices (3), preferentially of the presence of the ball inthe wireless mouse type. 14) Device for controlling a computer system(1) according to any one of the preceding claims, characterized in thateach one of said pointing devices (3) comprises moreover push-buttons ina number at least equal to 2, preferentially 7, whose sequences ofbinary data representative of their states are included in said binarydigits. 15) Use of the device for controlling a computer system (1)according to any one of the preceding claims, characterized in that saidinformation processing system (1) comprises: a central processing unitpreferentially of the portable computer (1) type, a peripheral displaypreferentially of the LCD tablet type (47) adaptable to an overheadprojector (48), or a portable video-projector, an application softwareset of the office automation or communication type, or specific of afunction or a trade, and in that said use is preferentially collectiveinitiation with microprocessing and collective training to the use ofsaid software. 16) Use of the device for controlling a computer system(1) according to any preceding claims 1 to 14, characterized in thatsaid information processing system (I) comprises: a central processingunit preferentially of the portable computer (1) type. a peripheraldisplay preferentially of the LCD tablet (47) type adaptable to anoverhead projector (48), or a portable video-projector, an applicationsoftware set of the computer-assisted presentation type, and in thatsaid use is preferentially commercial presentation making it possible toan individual of a group of customers to choose a product or service bythe means of said pointing devices (3), and to visualize informationabout said product or said service. 17) Use of the device forcontrolling a computer system (1) according to any preceding claims 1 to14, characterized in that said information processing system (1)comprises: a central processing unit preferentially of the portablecomputer (1) type, a peripheral display preferentially of LCD tablet(47) type adaptable to an overhead projector (48), or a portablevideo-projector, an application software set of the computer-assistedlearning type, and in that said use is preferentially the collectivetaking of multiple-choice examinations the answers of which are selectedby the means of said push-buttons of said pointing devices (3). 18) Useof the device for controlling a computer system (1) according to any oneof the preceding claims, characterized in that said computer system (1),said pointing devices (3), and said electronic box (4) are placed on atrolley held at the disposal of users, trainers, presenters or teachers,to be taken along and used in buildings without special electric wiring.19) Use of the device for controlling a computer system (1) according toany one of the preceding claims, characterized in that computer system(1) comprises moreover keyboard simulation software making it possibleto simulate a keystroke by pointing the simulated image of said key bymeans of one of said pointing devices. 20) Use of the device forcontrolling a computer system (1) according to any one of the precedingclaims, characterized in that said communication program includessequences of identification binary data in said binary digits foridentifying said pointing devices (3) which are transmitting, and inthat said computer system (1) comprises moreover software for allottinga cursor (54) of different form and/or color to each one of saidpointing device (3), according to said sequences of identificationbinary data received.